There is a recognized need for devices to lay down and retrieve highway markers, as exhibited by the numerous patents directed to the subject. However, it is not known if any are actually in use, and if they are in use, the usage appears quite limited.
In practice, three people are needed to lay down and also to retrieve the highway markers. One person drives a truck, a second person stacks or unstacks the highway markers one at a time and hands/receives them relative to a third person who leans out in the path of traffic and sets/grabs them on the highway. This exposes one or more of the people to the dangers of traffic and results in a high labor cost. Some of the above-mentioned patents involve devices that do eliminate one or two workers, however, they appear to suffer in one or more of high complexity, high cost, low capacity, large size and difficulty of storing or retrieving highway markers.